According to a new study, published in the journal Scientific Reports, older adults with irregular sleep patterns weigh more, have higher blood sugar and pressure, and a higher risk of cardiovascular disease; irregular sleepers also have increased stress and depression levels, psychiatric factors integrally tied to cardiometabolic disease.
Older adults with varied sleep-wake times weigh more, have higher blood sugar, risks of cardiovascular and cardiometabolic diseases.
“From our study, we can’t conclude that sleep irregularity results in health risks, or whether health conditions affect sleep. Perhaps all of these things are impacting each other,” said lead author Dr. Jessica Lunsford-Avery, of Duke University Medical Center.
“Still, the data suggest tracking sleep regularity could help identify people at risk of disease, and where health disparities may impact specific groups.”
The study involved 1978 older adults aged 54-93 years. People with diagnosed sleep disorders such as sleep apnea were not included.
Participants used devices that tracked sleep schedules down to the minute so researchers could learn whether even subtle changes — going to bed at 10:10 p.m. instead of the usual 10 p.m. — were linked to the health of participants.
The study also tracked the duration of participants’ sleep and preferred timing — whether someone turned in early or was a night owl.
According to these measures, people with hypertension tended to sleep more hours, and people with obesity tended to stay up later.
Of all three measures, however, regularity was the best at predicting someone’s heart and metabolic disease risk, the researchers found.
African-Americans had the most irregular sleep patterns compared to participants who were white, Chinese-American or Hispanic, the data showed.
“As one might expect, irregular sleepers experienced more sleepiness during the day and were less active — perhaps because they were tired,” Dr. Lunsford-Avery said.
“Perhaps there’s something about obesity that disrupts sleep regularity,” she added.
“Or, as some research suggests, perhaps poor sleep interferes with the body’s metabolism which can lead to weight gain, and it’s a vicious cycle.”
“With more research, we hope to understand what’s going on biologically, and perhaps then we could say what’s coming first or which is the chicken and which is the egg.”
Dr. Lunsford-Avery and colleagues plan to conduct more studies over longer periods in hopes of determining how biology causes changes in sleep regularity and vice-versa.
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Jessica R. Lunsford-Avery et al. 2018. Validation of the Sleep Regularity Index in Older Adults and Associations with Cardiometabolic Risk. Scientific Reports 8, article number: 14158; doi: 10.1038/s41598-018-32402-5
